TIL311 Equivalent
This circuit saved about £20 per digit (~£180 in total) for a PCI POST card that
was a previous design project. The first version of the card used the expensive
TIL311 displays (Now obsolete !). If the low current, 2mA per segment displays
are used, you won't have to use any driver buffers. You will also have to
increase the current limit resistors from the usual 270 Ohms to about 1K5.
A blanking input may be needed for some applications.
Below is the ABEL code for the binary to seven segment decoder.
MODULE BIN7SEG TITLE '4 BIT TO 7 SEGMENT DECODER' IN3,IN2,IN1,IN0 PIN istype 'com'; A,B,C,D,E,F,G PIN istype 'COM'; TRUTH_TABLE ([IN3,IN2,IN1,IN0]->[A,B,C,D,E,F,G]) [0,0,0,0] -> [0,0,0,0,0,0,1]; //[1,1,1,1,1,1,0]; [0,0,0,1] -> [1,0,0,1,1,1,1]; //[0,1,1,0,0,0,0]; [0,0,1,0] -> [0,0,1,0,0,1,0]; //[1,1,0,1,1,0,1]; [0,0,1,1] -> [1,0,0,1,1,0,0]; //[0,1,1,0,0,1,1]; [0,1,0,0] -> [1,0,0,1,1,0,0]; //[0,1,1,0,0,1,1]; [0,1,0,1] -> [0,1,0,0,1,0,0]; //[1,0,1,1,0,1,1]; [0,1,1,0] -> [0,1,0,0,0,0,0]; //[1,0,1,1,1,1,1]; [0,1,1,1] -> [0,0,0,1,1,1,1]; //[1,1,1,0,0,0,0]; [1,0,0,0] -> [0,0,0,0,0,0,0]; //[1,1,1,1,1,1,1]; [1,0,0,1] -> [0,0,0,0,1,0,0]; //[1,1,1,1,0,1,1]; [1,0,1,0] -> [0,0,0,1,0,0,0]; //[1,1,1,0,1,1,1]; [1,0,1,1] -> [1,1,0,0,0,0,0]; //[0,0,1,1,1,1,1]; [1,1,0,0] -> [0,1,1,0,0,0,1]; //[1,0,0,1,1,1,0]; [1,1,0,1] -> [1,0,0,0,0,1,0]; //[0,1,1,1,1,0,1]; [1,1,1,0] -> [0,1,1,0,0,0,0]; //[1,0,0,1,1,1,1]; [1,1,1,1] -> [0,1,1,1,0,0,0]; //[1,0,0,0,1,1,1]; END //For displays with common anode //commented out is just in case have common cathode
The design environment was Lattice Semiconductors ISPSesign Expert (Windows),
although there shouldn't be too much trouble translating it to your own package.
Download Lattice IspDesignExpert file
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